40 Hz Gamma Sensory Stimulation Effects on Memory Performance in Cognitively Healthy Older Adults

Abstract

Recent studies have demonstrated that a gamma sensory stimulation, light and sound flickering at 40 Hz, decreased Alzheimer’s symptoms and pathology in mice. Subsequent human trials showed similar results. Here we focus on preliminary behavioral results of a study in which cognitively healthy older adults use either the flicker intervention, or a control intervention consisting of constant light and sound, for one hour per day for 8 weeks. Participants will complete a face-name-occupation memory task, a spatial memory test using virtual reality (VR), and a line-detection task before and after the 8 weeks. It is hypothesized that there will be greater improvements in episodic, long-term, and spatial memory for those using the flicker. So far, preliminary data has shown both groups have higher accuracy in episodic memory after 8 weeks, likely due to learning effects. Preliminary spatial memory data demonstrates that flickering participants have a similar spatial error after 8 weeks, while those in the control group have increased spatial error. Preliminary data also shows the flickering group has similar memory performance after 8 weeks, while those in the control group are more prone to retrieval errors. There is no statistical significance in the current data analysis, but these patterns may become significant once sample size increases (N = 11). Based on current results, it is expected that the flicker group will have fewer spatial memory deficits and fewer long-term memory retrieval errors, and these results could give insight into flicker effectiveness in cognitively healthy older adults.